(a) Field
The invention relates to a mask and a mask assembly. More particularly, the invention relates to a mask used for depositing an organic layer, and a mask assembly.
(b) Description of the Related Art
Generally, as a representative example of a flat panel display, there are an organic light emitting display, a liquid crystal display, a plasma display panel, etc.
Among these, in order to manufacture the organic light emitting display, an electrode having a specific pattern, an organic emission layer, etc., are formed. The method for forming the electrode and the organic emission layer, etc., can be performed such as by a deposition method using a mask assembly.
More specifically, the organic light emitting display includes pixels that are a basic unit displaying images arrayed in a matrix form on a substrate, and an organic light emitting diode that has an anode, a first electrode, a cathode and a second electrode that are sequentially disposed with organic emission layers each emitting colored light such as red, green, blue or white colors, for each pixel. Organic materials of the organic emission layer are very vulnerable to moisture, oxygen, etc., such that thorough isolation thereof from moisture is employed during a process of forming the organic emission layer and after forming the organic emission layer. Therefore, performing patterning using a general photolithography process may be difficult. Consequently, the organic emission layer is formed using a mask in which pattern openings for penetrating deposition materials only through portions corresponding to each pattern thereof are defined.